The present invention generally relates to a leveling device, and more particularly to an improved device for leveling objects that rest on a floor or other substantially horizontal, but yet uneven or sloping surface.
The need to install and level objects on uneven or sloping floors has presented a long-standing problem, especially for various types of apparatuses including machines and appliances. Often floors are not plumb or perfectly flat, yet it is important that all the legs of an object contact the floor to provide adequate support and to equally distribute the weight of the object. If all the legs do not contact the floor, many problems can develop. For example, the outer cabinet and frame of an apparatus may become distorted over time due to nonuniform weight support, thereby impairing the proper operation of the apparatus. For example, this is especially true of refrigeration units, freezers, and ice machines which rely on a level installation to achieve proper sealing of their door gaskets. In the case of a motorized apparatus such as a washing machine, inadequate contact of all its legs with the floor is especially problematic because these devices have a tendency to vibrate and xe2x80x9cwalkxe2x80x9d across the floor if the floor is not level. Annoying xe2x80x9crockingxe2x80x9d problems with an apparatus may also result where the legs do not all contact the floor. Moreover, installations that are not level may be aesthetically undesirable by the inability to match the heights of adjacent cabinets, other equipment, or work surfaces.
Installers and manufacturers have attempted to resolve the leveling problem by developing approaches to compensate for uneven and sloping floors. Where the height of apparatus legs is not adjustable, for example, one such approach used by installers has been to place shims or wedges made of a suitable material under the legs. Obviously, this technique has numerous drawbacks. First, the apparatus must be manually lifted while such shims are placed under the legs, thereby often requiring more than one installer. This situation also increases the potential risk of back or other physical injuries to the installers. Second, the shims are not permanently mounted to the apparatus legs and may shift over time or become completely dislodged. This is especially problematic with motorized apparatuses which vibrate and xe2x80x9cwalkxe2x80x9d as described above.
Manufacturers have attempted to resolve the leveling problem with numerous design approaches. One technique which has been employed is to provide manually adjustable legs or supports, often referred to commercially as glides or levelers, under each corner of the apparatus""s outer cabinet. This consists primarily of a threaded vertical rod which on one end is screwed into a female threaded coupling near the apparatus""s corners. The rod typically has a pad or flattened base of some sort disposed on the opposite end which contacts the floor. The pad may also swivel or tilt relative to the longitudinal axis of the vertical rod. These manually adjustable supports, however, are still plagued by many of the problems encountered with the shim technique described above. For example, in many cases, the apparatus must be lifted manually to unload weight from the legs in order to rotate them and adjust their height. Furthermore, there is usually no way to access the rear legs for adjustment once the apparatus is slid into its final position because access is often not available from the rear or sides of the apparatus. This is particularly true of kitchen appliances such as refrigerators and dishwashers which are usually placed against a wall in the rear and have other equipment, cabinets, or a wall positioned against one or both sides of the apparatus. The manually adjustable leg design is also cumbersome to use, involving a time consuming trial and error approach to leveling the apparatus on uneven floors. The apparatus must often be slid into and out of its final position numerous times while gradual adjustments are made to the otherwise inaccessible rear support legs in hopes of finding the proper height of each rear leg.
Other approaches have been used with limited success in an attempt to overcome the many problems of leveling objects on uneven floors. For example, U.S. Pat. No. 4,518,142 to Sulcek et al. discloses a leveling system for appliances utilizing manually adjustable wheels or rollers for rear supports. Even though the appliance may be easier to push into its final position, the height of the rear supports must be adjusted before the appliance is slid into place, often without access to the final resting position of the rear supports on the floor. U.S. Pat. No. 5,749,550 to Jackson discloses a rear leveling system for refrigerators using rollers for rear supports. Although the rear supports are adjustable from the front of the appliance, the mechanism is complicated and requires virtually all parts to be fabricated from metal. Like many similar mechanisms, the manufacturing costs are high and they are prone to problems due to their complex design.
Accordingly, there is a need for a leveling device that is simple in design, economical to produce, and allows adjustment of the height of the rear supports or legs after the object is in place.
The invention is generally directed to an adjustable leveling device which can be used for any object, including various apparatuses such as equipment and appliances.
In accordance with one embodiment, the leveling device is comprised of a housing having a base portion, a top portion, and a substantially hollow portion disposed between the base and top portions. The hollow portion is adapted and configured to provide at least one load-bearing surface. In one embodiment, the housing may be fabricated by machining. In another embodiment, the housing may be made of plastic which in one embodiment is fabricated by molding.
The leveling device further comprises an elevation shaft having a longitudinal axis which may be disposed at least partially within the hollow portion and may have threads on at least a portion of its external surface. A means for restraining the elevation shaft from rotating relative to the housing may also be provided. In one embodiment, the elevation shaft restraining means comprises an opening disposed in the top portion of the housing through which the elevation shaft extends, the opening having a flat surface and a flat portion is configured on the elevation shaft to operably engage the flat surface in the opening to prevent the shaft from rotating. In another embodiment, the shaft restraining means comprises a slot extending along a portion of the longitudinal axis of the elevation shaft, an opening disposed in the top portion of the housing through which the elevation shaft extends, and the opening having a key to operably engage the slot to prevent rotation of the shaft. In yet another embodiment, the shaft restraining means comprises a key extending along a portion of the longitudinal axis of the shaft, an opening disposed in the top portion of the housing through which the shaft extends, and the opening having a slot to operably engage the key to prevent rotation of the shaft.
In accordance with one embodiment, the elevation shaft is axially movable to allow at least one end of the shaft to be completely retracted into the housing.
The leveling device further comprises a worm gear which may be disposed within the hollow portion of the housing. The worm gear has teeth and at least one end of the worm gear may have an extension protruding out from the housing which may be configured to facilitate rotation of the worm gear. The extension may be configured to receive a tool to rotate the worm gear, which in one embodiment may be a hex head. In accordance with one embodiment of the leveling device, the worm gear is made of plastic.
The leveling device further comprises a driven gear which may have internal threads that are engaged with the threads of the elevation shaft and external teeth that are engaged with the teeth of the worm gear. The driven gear is adapted and configured to operably engage the at least one load-bearing surface of the hollow portion of the housing such that no separate bearings are required with the leveling device.
In one embodiment, the driven gear may be a spur gear. However, in another embodiment, the driven gear may be a helical gear. The driven gear may also include a stem. In accordance with one embodiment, the driven gear may be made of plastic.
When the worm gear is rotated in opposite directions, concomitant rotations of the driven gear cause the elevation shaft to move axially up or down to provide leveling motions to an object attached to the leveling device.
The device further comprises a means for retaining the driven gear within the hollow portion of the housing. In one embodiment, the means for retaining the driven gear within the substantially hollow portion of the housing may be a collar that is fastened within an opening in the base portion. In another embodiment, the driven gear retaining means may be a load-bearing block that is fastened within an opening in the base portion; the block having a hole configured and adapted to receive the elevation shaft.
In accordance with one embodiment of the leveling device, a means may be connected to one end of the elevation shaft for protecting a nonuniform surface from damage by contact of the end of the shaft with the surface. In one embodiment, the surface protecting means may comprise a pad shaped as a round disk. In one embodiment, the elevation shaft is axially movable such that the pad may be completely retracted into the housing of the leveling device. In another embodiment, the pad may be rotably connected to the end of the elevation shaft to permit independent relative rotation between the pad and the shaft. The pad in yet another embodiment may be movably attached to the end of the elevation shaft to permit the pad to tilt at an angle relative to a plane perpendicular to the longitudinal axis of the shaft. In one embodiment, the angle may range from 0 to about 5 degrees.
In accordance with another embodiment of the leveling device, the surface protecting means may comprise a roller. In one embodiment, the roller may be pivotally mounted to the end of the elevation shaft to permit swiveling of the roller around the elevation shaft.
In accordance with one embodiment of the leveling device, the housing is adapted and configured to attach to an object. The top portion of the housing may be situated opposite the base portion of the housing, and each such portion may have at least one opening. The hollow portion of the housing may further comprise a first internal compartment with a first cross-sectional area parallel to the base portion and a second internal compartment with a second cross-sectional area parallel to the base portion. The second cross-sectional area may be smaller than the first cross-sectional area. The first internal compartment communicates with the second internal compartment and the at least one opening in the base portion. The second internal compartment communicates with the at least one opening in the top portion of the housing. A stepped transition may be provided between the first and second internal compartment which is adapted and configured to define at least one load-bearing surface. In one embodiment, the driven gear may have a top and bottom wherein the top contacts the load-bearing surface of the stepped transition without any separate bearings.
In accordance with one embodiment of the leveling device, the driven gear may be disposed in the first internal compartment of the housing. A stem may also be provided in another embodiment extending from the top of the driven gear, wherein the stem may be disposed in the second internal compartment of the housing.
In accordance with another embodiment of the housing of the leveling device, the hollow portion may define a gear cavity having a first cross-sectional area parallel to the base portion of the housing. The hollow portion may further define a gear stem cavity having a second cross-sectional area parallel to the base portion of the housing which is smaller than the cross-sectional area of the gear cavity. The gear stem cavity may communicate with the opening in the top portion of the housing wherein the gear cavity is coaxially aligned with the gear stem cavity and a stepped transition is formed between the gear cavity and the gear stem cavity; the stepped transition providing a load-bearing surface.
In another embodiment of the leveling device, the housing may comprise a substantially rectangular cavity for the worm gear. The worm gear cavity may have an open top, a closed bottom, two elongated sides, and two ends with an opening disposed in each end. The shape of the closed bottom may be semi-circular.
In accordance with one embodiment, the housing of the leveling device may be adapted and configured to attach to an object in an inverted position whereby the base portion is oriented upwardly and the top portion is oriented downwardly. In this embodiment, a load-bearing block may be inserted within the opening in the base portion of the housing, the block having a hole configured and adapted to receive the elevation shaft, thereby providing a load-bearing surface for support of the load imposed on the leveling device by the object.
A method for leveling an object is also provided which may comprise the steps of:
(a) providing at least two leveling devices each comprising:
a housing having a base portion, a top portion, and a substantially hollow portion;
an elevation shaft having a longitudinal axis disposed at least partially within the hollow portion, at least a portion of the shaft having threads on its external surface;
a worm gear having teeth disposed within the housing, at least one end of the worm gear having an extension protruding out from the housing and configured to receive a tool to facilitate rotation of the worm gear;
a driven gear disposed within the hollow portion having internal threads engaged with the threads of the elevation shaft and external gear teeth engaged with the teeth of the worm gear;
means for retaining the driven gear within the hollow portion; and
means for restraining the elevation shaft from rotating relative to the housing,
whereby upon rotation of the worm gear in opposite directions and concomitant rotations of the driven gear, the elevation shaft is caused to move axially up or down;
(b) providing a tool configured to operably engage the at least one end of the worm gear extending out from the housing;
(c) providing an object to which the at least two leveling devices are mounted, the object providing access for the tool to engage the at least two leveling devices;
(d) engaging the tool with the extension of the at least one end of the worm gear protruding out from the housing of one of the at least two leveling devices; and
(e) rotating the worm gear of one of the at least two leveling devices with the tool to raise or lower the object.
In one embodiment, the method for leveling an object described above comprises rotating the worm gear of at least one of the leveling devices to level an object. In another embodiment, the method for leveling an object described above comprises rotating the worm gear of both leveling devices to level object. In accordance with one embodiment, an appliance is the object to be leveled by the method described above.